Prophylactic devices are used to prevent the transfer of infection, bacteria and viruses from an environment to a body member on which the device is mounted. Prophylactic devices include but are not limited to catheters, valves, gloves, and so forth. For example, condoms are used to protect the user from venereal diseases and for birth control, and surgical gloves are used to protect the user from infection. In order to allow the protected body member to move freely and to respond to external stimulus, the device must be as thin as possible, but this reduces the protection it provides. For many years prophylactic devices have been made of latex rubber, but when a latex condom is sufficiently thin, it reduces overall strength, is subject to breakage, and there is an increased risk that it will have pin holes that are large enough to permit the passage of viruses such as the HIV. Accordingly, latex condoms must be manufactured and tested with great care and consequent expense. Also, some people are allergic to latex.
It has been found that prophylactic devices made of polyurethane, in contrast to latex, can be very thin so as to provide a good sense of feel while at the same time being very strong, and free from pinholes. Also, polyurethane due to its synthetic nature is typically more nonallergenic than latex.
In U.S. Pat. No. 4,684,490 a method for manufacturing condoms is described in which a mandrel having the general shape and dimensions of a condom is dipped into a solvent solution of a polyurethane polymer and heated in air after being withdrawn therefrom so as to dry the polyurethane. The dried polyurethane which now forms a condom is then removed from the mandrel.